1. Field of the Invention
The invention relates to marking the back side of sheet material to enable openings to be accurately located and cut into the material.
2. Brief Description of the Prior Art
Plasterboard, also known as Sheetrock.RTM., wallboard and gypsum board, has been used to replace plaster in construction for several decades. In comparison to plaster, plasterboard installs rapidly and requires substantially less manual labor. Plasterboard, however, still has installation problems which the industry has been attempting to solve.
Not the least of these problems is the marking of specific areas to be cut out. Currently these areas, such as for outlet boxes, heating vents, etc., are measured vertically and horizontally, from the adjacent plasterboard and floor or ceiling. The measurements are subsequently transferred to the plasterboard for cutting and installation. This is a time consuming process, even for professional installers. Plasterboard fortunately provides some leeway in that "mistakes" can be compensated through the use of spackle. The installation of wall paneling, however, does not provide any such leeway and a mistake in cutting can be quite costly.
The need for a rapid, easy to use marking device has been recognized in the construction field and is reflected in the prior art patents. U.S. Pat. No. 4,953,733 recognizes the need to mark plasterboard on the back side and has disclosed a device for use with electrical outlet boxes. The '733 device is provided with ears at each corner which fit within the outlet box. Arrow shaped marking elements are provided at the corners to engage the plasterboard. A securing screw can be inserted into a receiving hole within the body of the '733 device to secure the device to the outlet plug. Due to the construction of the '733 device, the marking elements are wedged into the plasterboard to mark the location of the plug outlet. Once the plasterboard is pressed onto the '733 device and removed for cutting the marking device is wedged into the plasterboard and must be removed prior to cutting the marked area. To prevent the device from being removed from the outlet with the plasterboard, the device must be secured through use of the securing screw. One of the problems with the '733 device is the necessity of securing the device to the outlet prior to measuring as well as removing the device after measuring, requiring substantial time on the part of the installer. Further, this device cannot be used on hard materials, such as paneling, tile or plywood. If the device is unsecured and retained within the plasterboard upon removal, the plasterboard must be maintained parallel to the wall during removal. Angling the plasterboard during removal could cause the ears of the device to catch on the outlet or even break up plasterboard.
U.S. Pat. No. 5,107,601, issued to Semchuck, uses a template consisting of indicia which define a hole pattern. These indicia are used to assist in drilling holes for mounting objects, such as towel bars. This device, however applies only to front mounted articles and does not provide any assistance with marking cut outs from the back of a rigid panel.
U.S. Pat. No. 4,969,269 discloses a device for punching cutouts through sheets of drywall. The '269 device has a pulley system which is used to cut the drywall in the shape of the outlet. The device is relatively expensive to produce and complicated to use.
U.S. Pat. No. 4,335,511 covers a marking device which marks the center of the outlet through use of a indicator which places an indentation in the wallboard at the center point of the outlet box. The wallboard is then horizontally placed, one half the depth of the wallboard is cut out in the shape of the outlet on the first side, the wallboard is turned over, and the remaining depth of the cutout is made. Cuts are made by striking the device which cuts into the wallboard. An inherent problem is that wallboard can break easily and unevenly when sharply struck, as it is brittle. Additionally, wallboard, is heavy and not easily moved or turned, rendering the '511 device awkward to use.
The disclosed invention overcomes the difficulties encountered in the prior art by providing a simple, inexpensive device for marking the reverse side of sheets of all types of material, such as paneling, plasterboard, floorboards, tiles, etc.